In today's commerce, merchants often utilize an array of different electronic devices, including point-of-sale (POS) devices, to engage in transactions with customers. For example, at a store, a merchant can use POS devices to conduct transactions with customers. While conducting these transactions, the POS devices may present user interfaces provided by the payment service that present and receive input from the merchant and/or the customer involved in a transaction. The POS devices can also send and receive data with a payment service for assistance in completing the transaction. For example, a POS device may send data to the payment service for processing a payment for a good or service provided by the merchant.